#include <stdio.h>
main( )
{
int i,s,n; 
while(scanf("%d",&n)!=EOF)
{
s=0; 
for (i=1;i<=n;i++)
s+=i*(i+1)/2;
if(n&1)
for(i=2;i<n;i+=2)
s+=i*(i+1)/2;
else
for(i=1;i<n;i+=2)
s+=i*(i+1)/2;
printf("%d\n",s);
}
}